The invention relates to a texturing jet for treating a filamentary material in a treatment duct formed between at least two superimposed body members, including at least one jet body for feeding a gaseous treatment medium and at least one vent portion provided in the treatment duct.
Multifilaments are threads made of synthetic polymers such as, for instance, polypropylene, polyamide, polyester or the like, which are applied in the most diverse fields. Apparatus for the production of multifilament threads comprise an extruder in which the starting material in granulate form is melted and pressed through a spinneret. Depending on the number of filaments desired per thread, the spinneret comprises the respective number of holes through which the synthetic material is pressed. Besides round cross sections, the holes of the spinneret may also have other cross sectional shapes in order to impart special properties on the filaments. The extrusion procedure is followed by a cooling process, after which the filaments are united to a thread. Depending on the purpose of use of the thread, various drawing processes, texturing processes and cooling processes follow, where-upon the yarn is finally wound on appropriate bobbins. Texturing serves to impart specific properties on the synthetic fibers or woven fabrics or the like resulting therefrom. If the yarns are used for carpets, the synthetic fibers are, for instance, treated with hot compressed air so as to cause appropriate crimping of the yarn, yet without individual filaments being allowed to break or tear. Those processes are known in the art as BCF texturing (BCF=bulked continuous filaments). The present invention is related essentially to such BCF texturing. In that process, crimps are introduced into the drawn yarn by hot air texturing. The texturing jets are operated in a range of from 145 to 150.degree. C. and at a pressure of 7 to 8 bars.
A texturing jet of the initially defined kind is described, for instance, in U.S. Pat. No. 4,949,441 A and the corresponding EP 495 886 B1. There, a filament yarn is sucked in through an injector and pulled downwards by the aid of hot air which is deflected accordingly. After this, the thread at a high speed and plastification temperature impinges on a tangle yarn plug within a chamber provided with a plurality of slots, thus being nonuniformly bent a great number of times, i.e., crimped. After texturing, the yarn is conducted over suitable cooling drums for cooling and, usually in a further step, is subsequently intermingled, which means that knobs are introduced so as to cause the filaments to be fixed within the yarn before the yarn is wound on appropriate bobbins. The texturing jet is comprised of a body member, a cover plate and an internal plate sandwiched therebetween and formed by a stack of laminae, one of which forms an elongate duct whose cross section changes both in breadth and in height between inlet and outlet. The body member is provided with two spaced-apart bores through which a fluid is fed for treating a strand material which is conducted through the duct. The stack-shaped laminate of the internal plate offers the advantage that only the duct-forming lamina will have to be replaced in the event of worn duct walls. However, the price paid for this advantage is the disadvantage that the construction of an internal plate including stacked laminae is highly demanding in respect to both production and mounting.
DE 30 19 302 A1 discloses a jet for intermingling yarns, which comprises a closed yarn travelling duct of rectangular cross section and gas feed ducts, wherein the duct widens stepwisely on one broadside or on both broadsides, the enlargements of the yarn travelling duct again narrowing to the original cross section.
U.S. Pat. No. 3,638,291 A describes a texturing jet in which the duct-forming body is comprised of but two parts whose oppositely arranged surfaces are plane, wherein the yarn travelling duct, which has a constant depth and includes lateral recesses, is formed in the surface of one of the bodies.
DE 38 29 150 A1 describes an air jet for pneumatic false twist spinning, which is comprised of several sections. The section that is arranged downstream of the section including the compressed air ducts is made of a harder, more wear-resistant material such as, e.g., ceramics.
DE 39 27 910 A1 describes a false twist spinneret provided for pneumatic false twist spinning, in which at least part of the inner wall of the blowing duct is provided with a coating or an insert made, for instance, of a ceramic material, in order to reduce the cross section of the exit opening.
The two last-mentioned documents describe spinning processes for staple fibers in which the yarn is not crimped or bulked, but stretched and formed into a lower-strength yarn within the air jet. The technology described in those documents, therefore, differs substantially from the technology underlying the present invention. Moreover, replacement of the inserts involves relatively high expenses.